The present invention relates to field devices in process plants where each field device can be uniquely identified and is connected to a control system by way of a communication network and more particularly to a system for expeditiously actuating and finding the location of each such unit.
A large number of field devices are installed in complex and/or physically extended process plants, in order to control the technical process in the process plant. These include measured value sensors for physical variables such as pressure, temperature, flow rate, concentration and the like, as well as actuators for operating valves, flaps, feed means and the like.
In the event of a defect or fault, the faulty field device must be identified and located as quickly as possible, in order to allow it to be repaired locally, or in order to allow the faulty field device to be replaced.
All the field devices in a process plant are included in a hierarchical structure of control loops comprising control devices. The control devices are in this case combined in a control system which is matched to the process plant. The control system can in this case be installed centrally or in a decentralized manner. Independently of this, each field device in a given process plant can be identified uniquely, and can be logically associated with a plant part, via the control system means. The logical location process for each field device that is carried out in this way is, however, inadequate actually to find a faulty field device in the process plant locally, in a reasonable time.
Furthermore, identification systems, for example in accordance with DIN 6779, are known, on the basis of which each field device in a given process plant is identified on the basis of its installation location. However, detailed knowledge of the layout of the process plant is required to find a field device that is being looked for.
The invention is thus based on the object of specifying means which allow a field device in the process plant to be actuated and to be found specifically in the shortest possible time.
The invention is based on a process plant in which each field device can be identified uniquely and is connected to a control system via a communication network. Furthermore, the process plant has a locally oriented hierarchical structure and a plant identification system based on it.
The essence of the invention comprises a fixed-position device and a mobile device. The fixed-position device is associated with the field device, and is a component which cannot be separated from it. Details relating to the position of the installation location of the field device are stored in the fixed-position device such that they can be called up.
To this end, the fixed-position device comprises at least one processing unit, a programmable non-volatile memory and a communication device for wire-free communication.
The mobile device comprises at least one processing unit, a keyboard, a display unit and a communication device, which corresponds to the communication device in the fixed-position device, for wire-free communication.
When a defect occurs in a field device, an alarm message is sent to the control system via the communication network. Furthermore, the communication device for wire-free communication is activated, and continuously transmits the details relating to the position of the installation location of the field device, on the basis of the specific plant identification.
The position details relating to the faulty field device are received by the communication device for wire-free communication in the mobile device, and are visualized on the display unit.
This makes it possible for the servicing technician who is carrying the mobile device to go to and to find the faulty field device in the process plant specifically in the shortest possible time, without any detailed knowledge of the plant.